I have the ///M Performance wheel and would agree it doesn't blend as nicely as a Nappa one.
However I do like the feel of Alcantara and the wear is excellent (did have the ///M Performance steering wheel on my previous E90s and the steering wheels did not show any significant wear after 2yrs).
As for custom steering wheels the folks at LeatherInteriors do great work too :
http://leatherinteriors.carsdream.co.../en/realizacje
http://leatherinteriors.carsdream.co...php/en/page/19